mknod - create a directory or special or ordinary file
int mknod(const char *pathname, mode_t mode, dev_t dev);
mknod attempts to create a filesystem node (file, device
special file or named pipe) named pathname, specified by
mode and dev.
mode specifies both the permissions to use and the type of
node to be created.
It should be a combination (using bitwise OR) of one of
the file types listed below and the permissions for the
The permissions are modified by the process's umask in the
usual way: the permissions of the created node are (mode &
The file type should be one of S_IFREG, S_IFCHR, S_IFBLK
and S_IFIFO to specify a normal file (which will be cre
ated empty), character special file, block special file or
FIFO (named pipe), respectively, or zero, which will cre
ate a normal file.
If the file type is S_IFCHR or S_IFBLK then dev specifies
the major and minor numbers of the newly created device
special file; otherwise it is ignored.
The newly created node will be owned by the effective uid
of the process. If the directory containing the node has
the set group id bit set, or if the filesystem is mounted
with BSD group semantics, the new node will inherit the
group ownership from its parent directory; otherwise it
will be owned by the effective gid of the process.
mknod returns zero on success, or -1 if an error occurred
(in which case, errno is set appropriately).
EPERM mode requested creation of something other than a
FIFO (named pipe), and the caller is not the supe
ruser; also returned if the filesystem containing
pathname does not support the type of node
normal file, device special file or FIFO.
EEXIST pathname already exists.
EFAULT pathname points outside your accessible address
EACCES The parent directory does not allow write permis
sion to the process, or one of the directories in
pathname did not allow search (execute) permission.
pathname was too long.
ENOENT A directory component in pathname does not exist or
is a dangling symbolic link.
A component used as a directory in pathname is not,
in fact, a directory.
ENOMEM Insufficient kernel memory was available.
EROFS pathname refers to a file on a read-only filesys
ELOOP Too many symbolic links were encountered in resolv
ENOSPC The device containing pathname has no room for the
SVr4 (but the call requires privilege and is thus not in
POSIX), 4.4BSD. The Linux version differs from the SVr4
version in that it does not require root permission to
create pipes, also in that no EMULTIHOP, ENOLINK, or EINTR
error is documented.
The mknod call cannot be used to create directories or
socket files, and cannot be used to create normal files by
users other than the superuser.
There are many infelicities in the protocol underlying
NFS. Some of these affect mknod.
read(2), write(2), fcntl(2), close(2), unlink(2), open(2),
mkdir(2), stat(2), umask(2), mount(2), socket(2),